1. Field of the Invention
The present invention relates to an automotive seat with a walk-in device, of the type having a memory device, in which the seat may be moved forwardly for walk-in operation and positively returned to its predetermined home position, and in particular, relates to the walk-in device for effecting the walk-in operation of the seat so that the forward inclination of the seat back releases the locked state of a slide device of the seat and causes the seat back to move forwardly.
2. Description of the Prior Art
For use in a walk-in seat, there has been available various kinds of walk-in devices which, in most cases, are provided with a memory device, whereby the seat may be moved forwardly for allowing the entry of a passenger into a rear seat and returned to its predetermined home position. A conventional example of such walk-in device is shown in FIGS. 1(A) and 1(B) of the accompanying drawings. Referring to the prior art shown, a walk-in device (3') is provided laterally of a slide rail device (2') which consists of an upper rail (22') and a lower rail (21'). The upper rail (22') is slidably fitted to the lower rail (21') and may be brought to a locked or unlocked state via a locking mechanism (51') by operation of an operation lever (54'). The locking mechanism (51') has plural holes into which engaged are some of plural teeth (52') formed at the lower rail (21') and is actuated by rotation of the operation lever (54') so as to bring the holes into engagement with or disengagement from the teeth (52'), thereby locking or unlocking the sliding movement of the upper rail (22') along the lower rail (21'). To that operation lever (54'), operatively connected is the walk-in device (3') which comprises a release wire (34'), an arcuate rotatable plate (32') rotatably mounted at the lower rail (21') and a plate-like piece (30'). The release wire (34') is connected to a seat back (not shown) of the seat, and, according to this prior art, when the seat back is forwardly inclined, the release wire (34') is pulled, causing the movable plate (32') to rotate about a pivot point (32'a) to contact and push the plate-like piece (30') welded to the lever (54'). Thus, with rotation of the rotatable plate (32'), the lever (54') is caused to rotate via the plate-like piece (30') in a direction to release the engagement of the holes of the locking mechanism (51') with the teeth (52'), and then, the locked state of the slide rail device (2') is released, and by means of a spring (not shown), the seat is caused to move forwardly via the sliding movement of the upper rail (22') upon the lower rail (21').
The above-mentioned prior art, however, has been found defective in a great likelihood of the rotatable plate (32') being worn or abraded, due to the fact that in operation, the rotatable plate (32) is initally at its side edges in a full contact with the plate-like piece (32'), but with further rotation, such contact of the plate (32'), because of its side edges being inclined relative to the plate-like piece (30) and only contacted with one side edge of the same, is transformed into a small localized or point contact with respect to the plate-like piece (30'). As a result, the contact area of the rotatable plate (32') against the plate-like piece (30') will be gradually abraded and recessed, with the result that the rotation amount of the plate-like piece (30') will become so reduced that the lever (54') is not rotated sufficiently to effect the diesengagement of the holes of the locking mechanism (51') and the walk-in device (3') is not worked. Additionally, in case that the operative stroke of the release wire (34') is relatively small, there is need to reduce the length (l) of the rotatable plate (30') in order to attain a sufficient rotation amount of the plate-like piece (30'), in which case, the load of the rotatable plate (32') against the plate-like piece (30') is increased in excess, which makes it more easily for the plate-like piece (30') to be worn or abraded, thus resulting in the failure of the walk-in device (3').
The above-described prior art is provided also with a memory device (4'), which comprises a base plate (31'), a memory plate (41') which is rotatably mounted via a pin (41'c) on the base plate (31') and a guide plate (41'e). In brief, according to this conventional memory device (4'), when the plate-like piece (30') is rotated in the operation of the walk-in device (3'), the projection (32'a) formed on the rotatable plate (32') is engaged into the recessed part (41'd) of the memory plate (41'), then keeping unlocked the locking mechanism (51'), and with the movement of the upper rail (22), the hook part (41'b) of the memory plate (41') is displaced beyond the end (41'e-1) of the guide plate (41'e), whereas when the upper rail (22) is moved back, the hook part (41'b) is also moved back and rides over the end (41'e-1), thereby rotating the memory plate (41') to disengage the projection (32'a) from the recessed part (41'd) and allowing the locking mechanism ((51') to effect its locking at the previously locked area of the teeth (52), whereupon the seat is returned to its normal set position. However, the defective aspect of this memory device (4') is that the provision of the guide plate (41'e) under the lower rail (21) forms a downward protrusion, which results in an unfavorable increased height of the slide rail (2'), thus increasing the height of the seat and taking up much of the interior space of automobile, and that the guide plate (41'i e) is easily subjected to damage, due to its projecting nature, during transfer or assemlage thereof, and further becomes a cause of giving flaw to a carpet on the floor of automobile.